The present invention relates to flame retardant, transparent blends of aromatic polycarbonate and poly(aryloxysiloxane) which blends have been found to have high impact strength.
Prior to the present invention, as shown by Lewis, U.S. Pat. No. 4 954,549, flame retardant substantially transparent aromatic polycarbonate compositions were provided by incorporating into the aromatic polycarbonate a triarylsilicon material, such as triphenylsilanol. A suitable organic solvent was used which was allowed to evaporate after the triarylsilicon material had been properly dispersed. The resulting blend was then compression molded.
In copending application Ser. No. 07/497,155, filed Mar. 21, 1990, now U.S. Pat. No. 5,041,514 and incorporated herein by reference, there are shown Polymeric Reaction Products of Biphenols and Organosilicon Materials, such as poly(aryloxysiloxane)s, and preferably poly(silyloxybiphenyleneoxide)s, hereinafter referred to as "PAS", consisting essentially of chemically combined groups of the formula, ##STR1## where R in formula 1 is selected from the same or different C.sub.(1-8) alkyl radicals, and R.sup.1 is selected from the same or different C.sub.(1-13) monovalent hydrocarbon radicals, and C.sub.(1-13) monovalent hydrocarbon radicals substituted with monovalent radicals inert during condensation. PAS of formula (1) has been found to have improved hydrolytic stability. It is a high molecular weight injection moldable material exhibiting flame resistant properties.